<template>
    <div>
        <router-link class="header-abs" tag="div" to="/" v-show="showAbs">
            <div class="iconfont header-abs-back">&#xe658;</div>
        </router-link>
         <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
            <router-link  to="/">
                <div class="iconfont header-fixed-back">&#xe658;</div>
            </router-link>
             景点详情
         </div>
   </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll) // 全局事件解绑
  }
}
</script>

<style lang="stylus" scoped>
  .header-abs
   position: absolute
   left: .2rem
   top: .2rem
   width: .8rem
   height: .8rem
   line-height:.8rem
   border-radius: .4rem
   text-align: center
   background: rgba(0 , 0 , 0 , .8)
   .header-abs-back
     color: #fff
     font-size: .4rem
  .header-fixed
   position fixed
   z-index: 2
   top:0
   left:0
   right:0
   height:.86rem
   line-height:.86rem
   text-align:center
   color:#fff
   background:#00bcd4
   font-size:.32rem
   .header-fixed-back
    position absolute
    width: .64rem
    text-align: center
    left:0
    top:0
    font-size:.42rem
    color:#fff
</style>
